Well casing and tubing suspension assembly



May 21, 1963 e. OTTEMAN ETAL 3,090,640

WELL CASING AND TUBING SUSPENSION ASSEMBLY Filed May 4, 1959 FIG.4

INVENTORSZ L. G. OTTEMAN N, B. NEWMAN J. A. HAEBER BY: J-Lhflmflg.

HEIR AGENT 3,090,640 WELL CASING AND TUBING SUSPENSION ASSEMBLY Lloyd G. Otteman, Nicholas B. Newman, and John A.

Haeber, Houston, Tex., assignors to Shell Oil Company,

a corporation of Delaware Filed May 4, 1959, Ser. No. 810,741 6 Claims. (Cl. 285-3) This invention relates to the completion of oil and gas wells and pertains more particularly to a method and apparatus for suspending long strings of pipe such as well casing and tubing in a well.

In the field of well drilling operations it is well known that it is necessary to support in a borehole multiple strings of pipe such as well casing and well tubing. It is general practice to effect a seal between the various strings of pipe at the point of support so that the fluid pressures between the various strings of pipe can be controlled independently of one another. The suspension of the various strings of pipe and the installation of seals between the individual strings is accomplished at the wellhead where each successively smaller string of pipe is provided at the top thereof with a pipe hanger by which it is suspended in its individual spool piece which constitutes part of the wellhead assembly. Since all work is done at the surface of the earth, it is quite easy for workmen to assemble this equipment for suspending the pipes by the use of hand tools.

However, to date there has been no system whereby a plurality of strings of pipe, such as well casing and tubing, can be successfully suspended in a well drilled at an offshore location where the wellhead is positioned on the bottom of the ocean in, say, 50 to 1500 feet of water.

It is therefore a primary object of the present invention to provide a method and apparatus by which an operator, positioned at a remote location, may suspend and seal various strings of pipe in a well where the wellhead is positioned on an ocean floor.

A further object of this invention is to provide a poweroperated apparatus adapted to be positioned in a wellhead to clamp various strings of pipe which may be individually or simultaneously installed therein. A further object of the present invention is to provide an apparatus whereby casing may be set above an intended set point in the well in case the casing sticks before the total length is run.

These and other objects of this invention will be understood from the following description of the invention taken with reference to the drawing, wherein:

I and FIGURE 4 is a view taken in longitudinal cross-section of either of the slip assemblies diagrammatically illustrated in FIGURE 1.

Referring 'to the drawing, the well casing and tubing suspension assembly of the present invention will be called a pipe suspension assembly 11 which may comprise one or more sections, the'number of sections depending upon the number of strings of pipe that are to be suspended from the assembly. In FIGURES 1-3 the pipe suspension assembly 11 is shown as having upper and lower sections 11a and 11b, respectively, since it is desired to suspend tlaree strings of pipe 12, 13 and 14, as shown in .ifihfidh Patented May 21, 1953 FIGURE 3. The outermost pipe string 12 will be known as the surface casing of the well for purposes of description, pipe string 13 will be described as the intermediate string casing, and pipe string 14 as the oil string casing. The number of strings of casing to be employed depends mainly upon the depth to which the well is drilled, the number of times the size of the drill bit was reduced, the formations, lost circulation, abnormal pressures, etc. Although no surface conductor string is shown it is realized that the entire apparatus of FIGURE 3 could, if desired, be positioned upon a conductor string which would have been previously cemented into the ground. Additionally, when producing the well, a well tubing string may be suspended within the oil string casing 14.

The pipe suspension assembly 11 is essentially a thickwalled tubular housing, the sections 11a and 11b thereof being fixedly secured together in any suitable manner such as, for example, by bolting flanges 15 and 16 together. The upper and lower sections 11a and 11b of the suspension assembly are provided with individual slip assemblies 17a and 17b, respectively, as shown in FIGURE 3. Each slip assembly is capable of suspending a string of pipe therefrom with the third string of pipe 12 being suspended from the bottom of the lower section 1112 of the suspension assembly in any suitable manner such, as by welding. During drilling operations a hydraulic ram type tubing head 21 may be connected to the top of the suspension assembly 11 with a connector head 22 being provided thereabove for connecting other equipment, as desired.

As shown in FIGURE 4 of the drawing, each section of the pipe suspension assembly, for example section 11a, is provided with a large bore passing coaxially therethrough, through which strings of pipe may pass or be positioned during the drilling and completion of the well. Wherever a slip assembly is to be located, the thick wall of the suspension assembly is machined or otherwise formed so that a substantial recess 24 is provided, the lower portion of said recess sloping inwardly to form the tapered face of a slip bowl 25. A plurality of slips 26, preferably three in number, are mounted within the slip bowl 25, in sliding contact therewith, for both axial and radial movement. Both the inner and outer faces, 27 and 28, respectively, of the slips 26 are smooth with the outer face 28 having the same slope as that of the slip bowl 25 while the inner face 27 slopes in the same direction, although not necessarily at the same angle.

A number of grooves, equal in number to the number of segments or slips 26, are preferably cut in the sloping face of the slip bowl 25, forming keyways 31 in which slip keys 32 may slide, the slip keys 32 being fixedly attached to the outer face of the slips 26. By the use of the keys 32 and keyways 31, the slip segments 26 remain positively aligned with respect to each other within the slip bowl 25 thus preventing movement of the segments of the slips around the inner face of the bowl.

Mounted in each of the slip segments 26 is a segment of an annular sealing element or packer 33 which is held in place by a segment of a packer retaining ring 34 which may be secured as by one or more bolts 35 to the body of the slip 26. When the sealing element 33 is in its operative position, that is, when the slip 26 and the packer retaining segment 34 has been forced against the seat 36 formed at the bottom of the bowl 25, the sealing element will be expanded so that its outer face seals against the slip bowl 26 while its inner face seals against the string of pipe centrally located between the slip segments 26. At the same time the sides of each of the sealing element segments 33 expand to seal against each other to form a complete sealing ring. Normally each slip segment 26 is releasably retained in its inoperative or retracted position by positioning means, such as a shear pin 37 which may be inserted through a hole 38 in the wall of the suspension assembly. The shear pin holes are sealed in a fluidtight manner to prevent escape of annulus pressure.

Positioned above the slip segments 26 are a slip segment positioning ring 41 and a drive ring 42. Each slip segment 26 is connected to the slip segment positioning ring 41 by a bolt 43 having a large head which is positioned in a recess 44 above a radial slot 45 therein. Thus, by having the head of the bolt 43 lower than the depth of recess 44, and the shank of the bolt 43 smaller than the width of the slot 45, the bolt 43 together witl the attached slip segment 26 is allowed to move radially Within the slot 45 below the drive plate 42.

Mounted in a pressure chamber 46 formed within the wall of the section of suspension assembly 11 is a drive piston 47 which is preferably fixedly secured at its lower end to the drive ring 42. Each of the pressure chambers 46 of the assembly is in communication, through a radial conduit 48, with a circumferential conduit 51 by which a hydraulic fluid may be applied through port 52. If desired, the drive pistons 47 could be connected directly to the top of the slip segments 26, but the use of a drive ring 42 is preferred to assure that equal force is applied to each of the slip segments 26 when they are being set against a pipe. Likewise, in some cases the slip segment positioning ring with its slots 44 and the bolts 43 movable therein may be omitted in installations Where the use of keys 32 and keyways 31 are sufficient to keep the slip segments 26 aligned.

Slidably mounted for axial movement along the sloping inner face 27 of each of the slip segments 26 is an auxiliary slip segment or slip means 53 having a vertical serrated or toothed inner surface 54 and a sloping outer surface 55 which has the same angle as that of the inner surface of the slip segment 26. The wedge-shaped auxiliary slip segment or slip means 53 is of a thickness so that when it is in its retracted or inoperative position, as illustrated in FIGURE 4, it does not extend inwardly toward the center of the suspension assembly bore 23 a distance greater than the inner surface of the top of the slip segment 26. Likewise, the slip segments 26 are of a size and thickness such that no portion of the slip segments 26, while in their retracted or inoperative position, as illustrated, extends into the bore 23 of the pipe suspension assembly 11a. Thus, the teeth on the inner face of the auxiliary slip segments 53 are not subject to Wear by tools passing through or rotating within the bore 23 of the suspension assembly section 11a.

The auxiliary slip segments 53 are prevented from moving circumferentially by a key 56 formed on the inner face of slip segment 26 which mates with a keyway 57 cut or formed in the outer face of the auxiliary slip segment 53. The auxiliary slip segments 53 are normally held in the retracted or inoperative position by means of a releasable slip positioning or retaining pin 6% which is'slidably mounted within a recess 61 within the slip segment 26, and spring loaded by means of a compression spring 62, in a manner such that either end of pin 60 may slide from the recess 61. However, its normal position is that shown in FIGURE 4, with the inner end of the pin 60 extending into the auxiliary slip means 53 and the outer end of the pin 60 bearing against the inner wall forming recess 24.

Mounted in a recess 63 in the overhanging top of the slip segment 26 is a compression spring 64 which bears on the upper face of the auxiliary slip segment 53. The spring is so selected and designed that it applies a predetermined force against the top of the slip segment 53 to force it downwardly along the sloping inner face of the slip segment -26 while simultaneously urging the inner serrated face 54 against a pipe casing that is positioned within the bore 23 of the suspension assembly.

In operation of the apparatus of the present invention,

7 the equipment illustrated in FIGURE 1 of the drawing is set into a well and the surface casing 12 is cemented therein. Drilling operations can then be continued with the drill pipe extending through the pipe suspension assembly 11, surface casing 12, and-blow-out preventer 21. When the desired amount of additional hole has been drilled, the drill string and bit (not shown) are withdrawn from the well and an intermediate string of casing 13 is run into thepipe suspension assembly 11 to the lower section 11b thereof where the lower slips 1711 are set, as shown in FIGURE 2. i

In setting the slips a pressure fluid is applied through port 52 (FIGURE 4), conduit 48, and into pressure chamber 46 where the drive piston 47 is forced downwardly. This action causes drive ring 42 and adjacent components of slip segments 26 to move downwardly, shearing pin 37, thus allowing the slip segments 26'to move both downwardly and inwardly. During this time the keys 32 in the keyways 31 as well as bolts 43 in slots 45 maintain the relative position of the several slip segments 26 with regard to each other.

As the slip segments 26 move downwardly along the tapered slip bowl 25, the vertical outer surfaces of the slip segments 26 move away from the inner wall of the suspension assembly section 11a, thus allowing compression spring 62 to slowly withdraw the pin 61 from the auxiliary slip segment or slip mean-s 53 and force the pin out of the other side of the slip segment 26. When the pin 60 has been entirely withdrawn fromthe auxiliary slip segment 53, the compression spring 64 exerts a downward force against the top of the auxiliary'slip segment 53 causing it to move down along the sloping inner face 27 of the slip segment 26 which 'in' turn causes it also to move inwardly against the intermediate casing string 13 to lock the casing 13 into position, as shown in FIGURE 2. Just prior to the serrated auxiliary slips 53 biting into the outer walls of the casing 13, the packer retaining ring at the bottom of the slip segment 26 contacts the seat 36 formed in the suspension assembly section, thus causing the sealing elements 33 to be expanded radially both inwardly against the casing 13 and outwardly against the slip bowl 25 to efifectively form a fluidtight seal therein. At the same time the sealing elements expand ciroumferentially against each other at their ends to form a sealing ring. After being securely anchored, the casing may be cut off at any desired level above the slips.

With the intermediate string of easing set in a manner shown in FIGURE 2, drilling operations can then proceed in a conventional manner with a smaller size drill bit and the drill string extending through the pipe suspension assembly and through the intermediate string of casing. After the well has been drilled to its desired depth, the drill string and bit are withdrawn and the 'oil string casing 14 is inserted, suspended and sealed in the casing suspension assembly as shown in FIGURE 3"and in the same manner as described with regard to thesuspending of the intermediate casing 13.

We claim as our invention:

1. Apparatus forrsu'spend-ing a string of pipe within a well, said apparatus comprising a suspension body having an axial throughbore, a sloping-faced slip bowl being formed in said suspension body around a portion of the throughbore, a plurality of slip segments carried in circumferentially spaced relationship in said slip bowl in a normally retracted inoperative position and mounted for sliding movement along the sloping face thereof, the outer face of saidslip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in substantially the same direction, positioning means normally releasably connecting said slip segments to said suspension body in a retracted position out of the throughbore thereof, auxiliary slip means carried on the inner faces of said slip segments in .circumferentially spaced relationship with each other, the inner faces of said slip means being vertical and serrated horizontally, second positioning means releasably connecting said slip segments and said slip means to hold said slip means in a retracted position, moving means carried within said suspension body in contact with said slip means for normally urging said slip means to an extended position, and slip segment actuating means carried by said suspension body and-in contact with said slip segments for normally urging said slip segments downwardly along said slip bowl to release said first positioning means and subsequently to release said second positioning means on radial inward movement of said slip segments.

2. Apparatus for suspending and sealing a string of pipe Within a well, said apparatus comprising a suspension body having an axial throughbore, a sloping-faced slip bowl being formed in said suspension body around a portion of the throughbore, a slip segment seat formed at the bottom of said bowl, a plurality of slip segments carried in circumferentially spaced relationship in said slip bowl in a normally retracted inoperative position and mounted for sliding movement along the sloping face thereof, the outer face of said slip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in substantially the same direction, positioning means normally releasably connecting said slip segments to said suspension body in a retracted position out of the throughbore thereof, auxiliary slip means carried on the inner faces of said slip segments in circumferentially spaced relationship with other, the inner faces of said slip means being vertical and serrated horizontally, second positioning means releasably connecting said slip segments and said slip means to hold said slip means in a retracted position, moving means carried within said suspension body in contact with said slip means for normally urging said slip means to an extended position, slip segment actuating means carried by said suspension body and in contact with said slip segments for normally urging said slip segments downwardly along said slip bowl to release said first positioning means and subsequently to release said second positioning means on radial inward movement of said slip segments, and sealing means carried within said suspension body for sealing around a pipe positioned in the bore thereof upon seating of said slip segments.

3. Apparataus for suspendng and sealing a string of pipe within a well, said apparatus comprising a suspension body having an axial throughbore, a sloping-faced slip bowl being formed in said suspension body around a portion of the throughbore, a plurality of slip segments carried in circumferentially spaced relationship in said slip bowl in a normally retracted inoperative position and mounted for sliding movement along the sloping face thereof, the outer face of said slip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in substantially the same direction, positioning means normally releasably connecting said slip segments to said suspension body in a retracted position out of the throughbore thereof, auxiliary slip means carried on the inner faces of said slip segments in circumferentially spaced relationship with each other, the inner faces of said slip means being vertical and serrated horizontally, second positioning means releasably connecting said slip segments and said slip means to hold said slip means in a retracted position, spring means bearing against said slip means for normally urging said slip means to an extended position, pressure-fluid-operated slip segment actuating means carried by said suspension body and in contact with said slip segments for normally urging said slip segments downwardly along said slip bowl to release said first positioning means and subsequently to release said second positioning means on radial inward movement of said slip segments, and sealing means carried within said suspension body around the bore thereof.

4. Apparatus for suspending a string of pipe within a well, said apparatus comprising a suspension body having an axial throughbore, a sloping-face slip bowl being formed in said suspension body around a portion of the throughbore, a plurality of slip segments carried in circumferentially spaced relationship insaid slip bowl and mounted for sliding movement along the sloping face thereof, the outer face of said slip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in substantially the same direction, shear pin means normally releasably connecting said slip segments to said suspension body in a retracted position out of the throughbore thereof, auxiliary slip means carried on the inner faces of said slip segments in circumferentially spaced relationship with each other, the inner faces of said slip means being vertical and serrated horizontally, spring-loaded pin means releasably connecting said slip segments and said slip means to hold said slip means in a retracted position, spring means carried within said suspension body in contact with said slip means for normally urging said slip means to an extended position, and pressure-fluid-operated slip segment actuating means carried by said suspension body and in contact with said slip segments for normally urging said slip segments downwardly along said slip bowl to release said first positioning means and subsequently to release said second positioning means on radial inward movement of said slip segments.

5. Apparatus for suspending a plurality of strings of pipe within a well, said apparatus comprising a plurality of suspension bodies fixedly connected together coaxially and having an axial throughbore, a sloping-faced slip bowl being formed in each suspension body around a position of the throughbore, a plurality of slip segments carried in circumferentially spaced relationship in said slip bowl in a normally retracted inoperative position and mounted for sliding movement along the sloping faces thereof, the outer face of said slip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in substantially the same direction, positioning means normally releasably connecting said slip segments to said suspension body in a retracted position out of the throughbore thereof, auxiliary slip means carried on the inner faces of said slip segments in circumferentially spaced relationship with each other, the inner faces of said slip means being vertical and serrated horizontally, second positioning means releasably connecting said slip segments and said slip means to hold said slip means in a retracted position, moving means carried within said suspension body in contact with said slip means for normally urging said slip means to an extended position, slip segment actuating means carried by said suspension body and in contact with said slip segments for normally urging said slip segments downwardly along said slip bowl to release said first positioning means and subsequently to release said second positioning meafis on radial inward movement of said slip segments, and a string of pipe of an inner diameter greater than the bore of said suspension body, the upper end of said pipe being fixedly secured coaxially to the lower end of the lowermost suspension body.

6. Apparatus for suspending a string of pipe within a well, said apparatus comprising a suspension body having an axial throughbore, a portion of the throughbore having a diameter greater than the portions above and below it and forming an annular recess, the body portion at the lower part of said recess being formed to slope inwardly forming a sloping-faced slip bowl, a plurality of slip segments carried in circumferentially spaced relationship in said slip bowl in a normally retracted inoperative position and mounted for sliding movement along the sloping face thereof, the outer face of said slip segments sloping at the same angle as said slip bowl, the inner faces of said slip segments sloping in the same direction, shear pin means normally connecting said slip segments to said suspension body in a retracted position, auxiliary slip means carried on the inner faces of said slip segments in circumferentially spaced relationship with each other, the inner faces of said slip means being vertical and serrated horizontally, spring-loaded pin means in said slip segments and' contacting said slip means to hold said slip means in a retracted position,

spring means carried within said suspension body in conand subsequently to release said second positioning means on radial inward movement of said sl-ip segments, and conduit means in said suspension body in communication with said piston means for applying a pressure fluid 15 thereto.

References Cited in the file of this patent UNITED STATES PATENTS Gattrell Apr. 12, Black Aug. 16, Penick et al. Mar. 9, Grifiin et al Apr. 19, Knox Sept. 9, Arrowood Sept. 22, Allen Sept. 28, Neilon July 5, Allen Feb. 24, Ortlotf Aug. 4, 

1. APPARATUS FOR SUSPENDING A STRING OF PIPE WITHIN A WELL, SAID APPARATUS COMPRISING A SUSPENSION BODY HAVING AN AXIAL THROUGHBORE, A SLOPING-FACED SLIP BOWL BEING FORMED IN SAID SUSPENSION BODY AROUND A PORTION OF THE THROUGHBORE, A PLURALITY OF SLIP SEGMENTS CARRIED IN CIRCUMFERENTIALLY SPACED RELATIONSHIP IN SAID SLIP BOWL IN A NORMALLY RETRACTED INOPERATIVE POSITION AND MOUNTED FOR SLIDING MOVEMENT ALONG THE SLOPING FACE THEREOF, THE OUTER FACE OF SAID SLIP SEGMENTS SLOPING AT THE SAME ANGLE AS SAID SLIP BOWL, THE INNER FACES OF SAID SLIP SEGMENTS SLOPING IN SUBSTANTIALLY THE SAME DIRECTION, POSITIONING MEANS NORMALLY RELEASABLY CONNECTING SAID SLIP SEGMENTS TO SAID SUSPENSION BODY IN A RETRACTED POSITION OUT OF THE THROUGHBORE THEREOF, AUXILIARY SLIP MEANS CARRIED ON THE INNER FACES OF SAID SLIP SEGMENTS IN CIRCUMFERENTIALLY SPACED RELATIONSHIP WITH EACH OTHER, THE INNER FACES OF SAID SLIP MEANS BEING VERTICAL AND SERRATED HORIZONTALLY, SECOND POSITIONING MEANS RELEASABLY CONNECTING SAID SLIP SEGMENTS AND SAID SLIP MEANS TO HOLD SAID SLIP MEANS IN A RETRACTED POSITION, MOVING MEANS CARRIED WITHIN SAID SUSPENSION BODY IN CONTACT WITH SAID SLIP MEANS FOR NORMALLY URGING SAID SLIP MEANS TO AN EXTENDED POSITION, AND SLIP SEGMENT ACTUATING MEANS CARRIED BY SAID SUSPENSION BODY AND IN CONTACT WITH SAID SLIP SEGMENTS FOR NORMALLY URGING SAID SLIP SEGMENTS DOWNWARDLY ALONG SAID SLIP BOWN TO RELEASE SAID FIRST POSITIONING MEANS AND SUBSEQUENTLY TO RELEASE SAID SECOND POSITIONING MEANS TO RADIAL INWARD MOVEMENT OF SAID SLIP SEGMENTS. 